Cryopreservation Freezing of semen and eggs

What is cryopreservation?

The word "kryos" comes from the Greek and means cold, the word "preservation" comes from the Latin "conservare", this means "to preserve". Cryopreservation is the possibility of freezing body cells in liquid nitrogen. The nitrogen has a temperature of up to -196°C. While the body cells are frozen, all metabolic processes of the cells are stopped. As soon as the body cells are thawed again, they return to their vital functions.

Cryopreservation is also called "gentle sleep", because the procedure is complex and yet gentle. The freezing process is computer-controlled and takes several hours.

Cryopreservation is often performed as part of artificial insemination, before treatment for a serious illness and social freezing.

If you have any fertilised eggs left over from In Vitro & ICSI, you can have them cryopreserved for use in a later cycle (e.g. if you want a sibling). The advantage of this is that you do not have to undergo hormone stimulation and puncture again. This form is becoming more and more important, as it is also more comfortable for the women and there is no longer a risk of overstimulation. You can read about the risks and side effects associated with this under hormone therapy.

Unfertilised eggs can also be cryopreserved in a process known as social freezing. Sometimes a child does not yet fit in with current life plans (e.g. career etc.) and so it can make sense for some women to have their eggs frozen. The unfertilised egg does not age during the process and can be used if needed.

Not only eggs (fertilised/unfertilised) can be cryopreserved. Sperm cells, testicular tissue or ovarian tissue can also be frozen.

The Embryo Protection Act (ESchG) stipulates that embryos may be cryopreserved in an emergency. An exceptional case would be, for example, if the woman has an accident before the transfer or cannot attend the transfer due to a serious illness.